1. Field of the Invention
The present invention relates to a display apparatus, and in particular, to a display apparatus including a self-luminescent device and a non-self-luminescent device.
2. Brief Description of the Prior Art
Digital electronic apparatus such as mobile phones, PDAs, and notebook computers have become necessary equipment as today's technology continues to advance. The capability of said digital electronic apparatus for storing power is relatively low, however, the display apparatus typically utilized in conjunction with such digital electronic apparatus tends to have a low power consumption as well. Additionally, because the digital electronic apparatus includes more and more functions, the display apparatus should be capable of displaying full color high resolution images and movies.
Normally, the display apparatus can be classified into one of two categories, these are a self-luminescent device or a non-self-luminescent device. Furthermore, the liquid crystal display (LCD) apparatus, which is of the non-self-luminous device category is classified into transmissive, reflective or transflective types.
The transmissive type LCD produces superior image quality when utilized in environments having average ambient light, however, the transmissive type LCD does not produce sufficient brightness under sunlight conditions. Additionally, the transmissive type LCD requires a back light unit which significantly increases it's power consumption.
The reflective type LCD can utilize surrounding light (i.e., ambient light) and also has good visibility when utilized in sunlight conditions. However, the reflective type LCD requires a front light unit to provide sufficient brightness during conditions when the surrounding light itself is insufficient. Additionally, the uniformity of the front light unit is poor thus the image quality of the reflective type LCD is reduced.
The transreflective type LCD includes both transmissive and reflective regions, thus the transmissive region can be utilized when the surrounding light is insufficient for producing a quality display image and the reflective region can be utilized when the transflective type LCD is utilized in a sunlight environment. Since the pixel size is fixed, the reflective region decreases while the transmissive region increases, and vice versa. Luminance of the plate maybe insufficient if the transmissive region is not enough, and the display apparatus may has poor displaying quality under sunlight if the reflective region is not enough.
The organic EL (Electro-Luminescence) is a display apparatus with high efficiency and less power consumption than the alternative types mentioned heretofore. However, the organic EL is a self-luminescent device and therefore has poor visibility under sunlight conditions similar to the transmissive type LCD previously discussed. The efficiency of the organic EL and the expected lifespan of the organic EL will decrease rapidly when brightness is increased to overcome sunlight conditions thereby helping the organic EL to be visible under sunlight.
To retain the advantages while avoiding the disadvantages of the display apparatus mentioned earlier, the display apparatus including a self-luminescent device and a non-self-luminance device is proposed, as shown in patents and patent applications U.S. Pat. No. 6,714,268, U.S. Pat. No. 6,912,021, U.S. Pat. No. 6,954,239, US20030052869, US20030103021, US20030201960, US20040125271, and WO2004053819. However, the inventions disclosed in these documents still have the disadvantage that the design and process of manufacturing is complicated because the control devices for each of the two display apparatus are provided on a same single substrate. The design of the circuit is difficult if a single switching device is used for controlling two different display apparatus.
Therefore, it is apparent that a new invention must be proposed to resolve the disadvantages cited above.